ok the fit valve is a tube looking thing on the intake manifold on the driver side it is facing the engine.on top of the fit ther is a round plate held on by 3 small screws take that plate of and turn in the big pug with a flat head screwdriver(its got greves that a flat head will fit in) if it has come un screwed be nice to it its made out of a soft plastick.if it is un screwed its leting in to much air.the fit changes you idle cold or hot when you engine is cold you want a higher idel so you engine stayes runing .so when the fit is cold it lets more air in to the engine to rase the idle when its hot it lets less air in to lower your idle.the iac(idle air control valve)is also on the intake it has one electrical conection and also has 2 collent hoses runing trew it it is controled by the ecm(engine control modual)to ajust the idle it has a small spining moter that contols a needle and seat set up to change how much air come into the engine.both are only used at idle ones you step on the gas pedle and open the tb(throtle body)thay are no longer used then the ecm moniters how much air the engine is puling and ads the right amount of fuel.


so spin in the fit puck and do the idle re lurn procuder listed on the last reply.if that dosent fix it i would try a new fit and a new iac.do the re lurn idle after that two.

hope this will help you.let me know